Of course he messed something up, which caused a rift in the space-time continuum. In order to avoid a never-ending loop of time paradoxes, the timeline reboot itself back to a particular point in time in which to start over with a hopefully different outcome: The point in Jurassic Park when Ian Malcolm is explaining about chaos theory during the land cruiser tour. Alan Grant (who was already feeling annoyed with Ian) felt strangely as if this whole thing had already happened, when suddenly he noticed Gollum sitting under a tree hugging what appeared to be Pandora's Box. "Nope," thought Alan, "that certainly hasn't happened before."